Pope John Paul II, speaking after a series of sex and child-molestation scandals that have jolted his church, has said priests who violate their celibacy vow bring tragedy on themselves and their victims.
"I share your sadness and disappointment when those entrusted with the sacred ministry fail in their commitment, becoming a cause of public scandal," the pope told U.S. bishops visiting the Vatican this week.
"These failures are tragic for the victims and for the clerics involved," the pope said. He called for prayers for "all those affected by this misconduct."
The pope said sex scandals had undermined people's trust in the church and had damaged priestly morale. He told the American bishops that "the failures of a small number of clerics" made it imperative that candidates for the priesthood were properly chosen.
Those men who could have difficulty respecting the celibacy regulation should be screened out in seminaries before they are ordained.
Only those seminarians with a "healthy psychosexual development and a sound human formation" are able to accept the church's rule, he said.
The pope and the Vatican have recently stepped up their campaign to stress the church's rule on celibacy in the wake of sex scandals involving priests and bishops.
Archbishop Robert Sanchez of Sante Fe, N.M., resigned in March amid allegations by five women that they had had sexual relations with him.
Archbishop Eugene Marino of Atlanta, the first black bishop in the American church's history, resigned in 1990 after officials learned of a two-year affair with a local woman.
Bishop Eamonn Casey of Galway in Ireland resigned last year after an American woman, Annie Murphy, revealed they had a child after an affair.
The Catholic Church in several countries, particularly the United States and Canada, has also been thrown into scandal over sexual misconduct by priests with minors.
A number of adults who claimed that as children they were molested by priests have filed lawsuits for huge sums of money against Catholic dioceses.
Earlier this year, U.S. bishops urged the Vatican to allow them to streamline procedures to defrock such priests so that local churches would not be legally and financially responsible for their actions.
In his speech to the U.S. bishops, the pope stressed that the church's rule on celibacy was permanent. The requirement was "not just a passing legal norm," he said.